Model airplane motor



July 26, 1949.

INVENTOR. Harry L Roderick BY MMMW ATTORNEYS.

Patented July 26, 1949 UNITED STATES PATENT OFFICE MODEL AIRPLANE MOTOR Harry L. Roderick, Oakland, Calif.

Application April 25, 1944, serial No. 532,586

3 Claims. (01. 185-37) Theinvention relates to motors for model airplanes and the like, and relates more particularly to a motor and motor mounting of the general nature disclosed in my United States Patent No. 1,936,072, issued November 21, 1933.

In motor driven devices of the character described, as set forth in my patent aforesaid, a plurality of driving units may be used to drive a single driven member such as a propeller or the like, and an appropriate change-over mechanism is used to connect the driven member to one source of energy until such source is substantially exhausted, and then to connect the driven member with a secondsource of energy. Heretofore in such change-over mechanisms, some difficulty has been experienced in effecting a proper disconnection of the driven member from the first source of energy anda proper connection of the driven member with the second source of energy; in that, just prior to the change-over, a part of the energy of the first set of rubber bands or similar source of energy will be frictionally dissipated in actuating the change-over mechanism. This decreases the power output of the first energy source and may prevent the change-over mechanism from properly operating. Under such conditions, in any event, a certain amount of chattering of the elements of the detachable connection, used inthe change-over mechanism, may occur, accompanied by wear and tear on the operating mechanism. In accordance with the present invention and as a principal object thereof, I provide a change over mechanism in a motor of the character described, which will provide for a quick, positive and clean release and separation of the first source of energy from the driven member and which willnot dissipate any energy of the first source of power in actuating such change-over mechanism.

The invention has other objects and advantages, some of which, with the foregoing, will be set forth in the following description of a preferred form of my invention which is illustrated in the drawing accompanying and forming a part of the specification. It is to be understood, however, that I do not limit myself to the specific embodiment shown in the said drawing and description, as I may adopt variations of this preferred form within the scope of my invention, as set forth in the claims hereof.

Referring to said drawing:

Figure 1 is a vertical sectional view of a. model 2 airplane constructed in accordance with the present invention;

Figure 2 is a vertical cross-section view similar to Figure 1 but showing certain of the operating parts in a diiferent position; v

Figure 3 is a perspective view in detail of the detachable connecting means between one of the motor units and the propeller of the airplane; and

Figure 4 is a front elevation, partly in section, of the motor unit taken substantially on the plane on line 4-4 of Figure 1.

The model airplane of the present invention, and as illustrated in the accompanying drawing, comprises a supporting frame 5 which supports the motor units and is preferably of a shape suitable to act as the frame of the fuselage of a model airplane, to which the wings, tail structure and the like may be fastened.

Secured to the forward end of the frame is a drive unit supporting plate 6, which is provided with a forward flange 1 and a rear flange 8 apertured to support a pair of longitudinally extending shafts l0 and II which are journalled in aligned bearing openings in the flanges l and 8 and are held against longitudinal movement by paired collars i 2 and I3 fixed to each of the shafts I0 and II at opposite sides of flange 1.

In accordance with my preferred arrangement, the shaft Ill is disposed in vertically spaced relation above the shaft II and forms a main motor shaft, or driven member, of the mechanism, extending forwardly of the flange 1 to support a propeller l4 at its front end. The propeller, as here shown, is fastened to a threaded end portion l6 ofthe shaft Ill between a pair of nuts H. The shaft. ll constitutes a second motor shaft, and when operated by its associated source of energy, is arranged to drive the shaft ID after energy from the directly connected source of energy for shaft I0 is substantially exhausted. The driving connection between the shafts l0 and II, as shown, includes gears I8 and I9 mounted on the outer collars l2 on these shafts, and adapted to be entrained upon rotation of the gear l9 by means ofan intermediate idler pinion H. The latter is carried on the forward end of a shaft 22 which is mounted in an inclined slot 23 in the flange 1 and is rockably journalled at its opposite end in a bearing 24 formed in the flange 8 so as to permit reciprocatory movement of the outer end of the shaft in the slot 23. As will be seen from Figure 4, the angle of slot 23 is such that when shaft I l is stationary, the gear 2| will gravitate to a position supported on and in mesh with the gear I9, but out of mesh with gear I8, and on rotation of the gear I9 in a counter-clockwise direction, with reference to Figure 4, the gear 2| will be advanced into mesh with the gear I8 to provide a driving connection between the shafts II and II).

The motive power for the shafts I and II is here derived from resilient sources of energy such as rubber bands 26 and 28, which extend longitudinally ofthe frame and are fastened at their rear ends to fixed hooks or the like supported in the frame. At its forward end band 26 is releas ably connected by a hook 34 to the rear end of an auxiliary clutch shaft 3|, while band 28 is releasably connected by a similar hook 34 to the rear end of the shaft H.

V 44 and 46 of the shafts Ill and 3| to effect relative Each band may be tensioned by releasing its front end ina manner hereinafter described, twisting the band, and re-securing the released end. After the Winding of the bands in this mannor. the pin 5! in shaft 3| may be seatedin a recess 41a of a sleeve 41 having a rectangular 'flsnse 1b s cured to the fram and th pi 39 shaft II may b en a d by a dog 36. as hereinafter described, to prevent unwinding of the ands by rotati n of these'shafts.

In accor ance with the present invention, the resilient means 26 provides the initial energ fo driving the propeller and is connected to the main driving shaft ill by a etachable connection. which is automatie iiy operative in response to the discharge of energy from the band 26 to effeeta disconnection of the band from the shaft Hi. This disconnection is of substantial importance, as will be. under tood, in order to prevent re-winding of he band 26 by ene gy derived from the second resilient means 28, which would materially shorten the effective operating period of the second spring motor, as well as for other purposes hereinafter r ferred to.

In effecting this disconnection of the band 26 and the shaft Iii, advantage-is taken of'the lengthening of the hand, during the discharge of stored energy therein, to operate at a predetermined length of the band a trigger mechanism for quicklyand positively severing the driving connection hetween'the hand 26 and shaft I0. 7

As shown in the accompanying drawing this severable driring connection comprises a sleeve 42 keyed to the shaft ID by means of a pin 56 fixed V in the shaft and extending through opposite longitudinal slots 5'! in said sleeve; A spring 43 compressed between a flange on the leftmost end of sleeve 42 and a washer abutting pin 56 tends to maintain sleeve 42 in the position in which it is shown in Figure 2 but the sleeve 42 may, on compression of the spring 43, be extended beyond the rightmost end 44 of shaft IQ and brought into surrounding relation with the forward end 46 of a ciutch shaft 3| as shown in Figure I, which shaft 3t 55; Supported in alignment with the shaft H] in a. bearing sleeve 41 carried by a transverse frame member QB, so as to. be capable of both rotational and longitudinal movement.

The right end 49 or the sleeve 42 is adapted to be secured to the shaft 3 I against longitudinal dis--' placement: and against rotational displacement in one. direction relative theretoby means of a bayonet type; connection including the pin- 5t carriedby the forward end portion of the shaft 3| which ext-en ds. radially from opposite sides thereof for n agement; in diametrically opposed bayonet slots is; formed in the end49: of the sleeve. These siots, as; will be; seen from Figure 3, include longitudinal hnlrtions. 53: which extend from the right end of the 4 sleeve to right angular portions 54, and the clutch connection is made by entering the pin 5| in the longitudinal portions 53 and movin the same longitudinally and rotationally into the slot portions 54.

Upon unwinding of the band 26 and resultant lengthening of said band, it will be seen that the expansion of spring 43 will move sleeve 42 leftwardly and the attached shaft 3| will thus be drawn towards the right end 44 of the shaft I0. In accordance with the present invention, camming means are provided upon the adjacent ends rotation of these shafts as an incident to the engagement thereof which ensues when band 26 has lengthened sufficiently. Such means are here provided in the form of cam faces 48 on the contiguous ends of the shafts I0 and 3| which, upon a forced longitudinal engagement will cause a relative rotational displacement between the shafts. The sleeve 42, while slidable on the shaft I0, is keyed for rotation therewith as has been described, so that the rotational displacement of the shafts Ii) and 3| is translated into a rotational displace ment between the sleeve and the shaft3| to effect a disconnection of the pin 5|. and bayonet slots. The pin 5| is thus moved in the bayonet slot 52 to an aligned position with the longitudinal portion 53 of the slot, and the sleeve 42 is'withdrawn from the shaft 3| by further expansion of spring 43 to sever the driving connection between the shafts 3| and l0.

The shaft I I isheld against rotation until substantial exhaustion of the energy stored in the band 26 by a dog 36 which is pivoted'to a lip 31 struck out of the fiange 8 at a position intermediate to the shafts I0 and II. The lower end 38 of the dog may be swung towards the flange 8 into the path of a transversely extending pin 39 on the shaft-l I to hold the latter against turning.

Release of the shaft II is effected by a displacef of the dog and release of the shaft II is accomplished by the sleeve 42, the leftward movement of which, described above, brings it into contact with the upper end 4| of the dog. In order to insure release of the dog 36 from pin 39, which presses quitestrongly against the dog, the upper end 4| of the dog 36 is shaped to present a cam surface to the end of sleeve 42.

Upon release of the shaft 3| by the sleeve 42, the former will withdraw under the remaining tension in the band 26 to a position engaging the pin 5| against the bearing sleeve 41 and the latter, as has been mentioned, is provided with opposed notchesilla in which the pin will engage to hold the shaft against further rotation and thereby prevent complete unwinding of the band 26, and possible entanglement thereof with band 28 r It will thus be clear that while the driving connection. between the resilient driving means 26. and the driven member in is absolutely positive during the operating period of the energy source 25, it will bequickly and cleanly severed upon the substantial. exhaustion of energy from a the source 2.6,, without chattering of the several parts, and also that the second drivemeam including the source of energy 23 and the shaft II will be quickly and cleanly released for rotation without any danger of a simultaneous connection of the two driving, sources with the single driven member. It will be further noted in connection with the driving connection between the shafts H and I0 including the gears 19, 2| and 18, that the intermediate idler gear 21 is normally held out of engagement with the gear l8 on the main shaft by gravity and that after a substantial exhaustion of energy from the source 28 the gear 2| will drop out of mesh with the propeller gear I8, should the propeller, due to favorable flying conditions, tend to rotate faster than the driving connection. Upon disengagement of the idler gear with the propeller gear, it will be clear that the propeller will be absolutely free to rotate and the plane may operate as a glider to substantially increase the period and length of flight.

A holding member 60 which, as illustrated in Figure 1, is formed to engage over the shaft [0 between the flange 8 and the left end of the sleeve 42 so as to hold the sleeve in the position in which it is shown in Figure 1, against the action of spring 43 permitting lock 36 to hold shaft H g sleeve, as above described. Preferably the member 60 is provided with a raised handle portion 65 to facilitate its positioning on and withdrawal from the shaft l0.

According to my invention the frontal portion of the ship supporting the propeller and its drive unit is detachably secured to the frame 5 so that the frontal portion may be removed with its attendant shafts and gears to draw shafts I0 and H and band 28 outwardly of the fuselage, to wind the bands and move the sleeve 42.

For this purpose I provide a separable connection between the frontal assembly and the body of the airplane, by securing ears 6| of plate 6 to a separable nose piece 58 and mounting the latter on supporting members 59 adjacent the front of the frame 5 by detachable snap fastener means 62. The latter, in the present construction, are simple ball and spring socket fasteners of the conventional glove fastener type and are preferably positioned at the portion of the abutting members 58 and 59 below the band 28.

I claim:

1. In a device of the character described, a

til)

driven member, a source of energy for driving said member, detachable clutch sections having bayonet locking means for holding said sections against separation, resilient means urging the separation of said sections, and means operative in response to a substantial release of energy from such source to unlock said bayonet means to effect a disconnection by said resilient means.

2. In a device of the character described, a driven shaft, resilient means for driving said shaft and changing in length with the potential energy stored therein, means slidably carried by said shaft and having a bayonet type connection with said first means, a spring urging the separation of said first and second means, and cam means controlled by a predetermined change in length of said driving means, caused by a substantial release of energy and the co-action of the spring, to effect a relative rotative displacement of said first and second means to disconnect said bayonet connection.

3. In a device of the character described, a

driven shaft, a source of energy, a shaft driven by said source in endwise alignment with said first shaft, means adapted to be yieldingly extended from said first shaft, detachable means securing said means to said second shaft against endwise movement thereon, and means operative in response to a substantial release of energy from said source to detach said second means to permit a rapid resilient withdrawal of said first means.

HARRY L. RODERICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,936,072 Roderick Nov. 21, 1933 1,995,447 Daniel Mar. 26, 1935 2,028,845 Reid Jan. 28, 1936 2,200,686 Beckman May 14, 1940 FOREIGN PATENTS Number Country Date 385,012 Great Britain Dec. 22, 1932 853,010 France Nov. 18, 1939 

